Acta Geographica Sinica ›› 2008, Vol. 63 ›› Issue (1): 23-33.doi: 10.11821/xb200801003

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Humidity Variability in the Arid Northwest China during LIA Derived from Different Proxy Records

CHEN Jianhui1, CHEN Fahu1, ZHANG Jiawu1, YANG Bao2   

  1. 1. MOE Key Laboratory of West China's Environmental System, Lanzhou University, Lanzhou 730000, China;
    2. Cold and Arid Regions Environmental and Engineering Research Institute, CAS, Lanzhou 730000, China
  • Received:2007-09-20 Revised:2007-10-23 Online:2008-01-25 Published:2008-01-25
  • Supported by:

    Key Project for National Natural Science Foundation of China, No.90502008; Innovation Team Project for National Natural Science Foundation of China, No.40421101

Abstract:

Eleven major humidity proxy records and other supplementary evidences including different natural archives such as ice-cores, sedimentary records, river terraces, lake-level fluctuations as well as historical documents are involved to reconstruct the humidity variability in the arid Northwest China during the Little Ice Age (LIA) from 1400 AD to 1920 AD. The result shows that as a whole, the LIA is a relatively humid period in this region, contrasting to last 100 years during global warming and medieval warming period. For instance, precipitation in high marginal mountains of the study area was of a high value reflected by the various proxy records from west Kunlun, Tianshan and Qilian mountains. Accordingly, the discharge of big endorheic rivers such as the Tarim and Keliya rivers increased; the surface areas of terminal lakes in desert field expanded, e.g., at Juyan Lake and Ebinur Lake; the water levels rose at lakes in intermontane basins, such as Bosten Lake, Balikun Lake and Qinghai Lake; the groundwater recharge rates in the Badain Jaran Desert were increased; and the water salinity of Sugan Lake also significantly decreased during the LIA. Furthermore, the humidity records with a relatively high resolution from the eastern-southern fringe of the arid Northwest China indicate that there is a secondary oscillation of wet and dry within the LIA. The relatively high humidity during the LIA in Northeast China possibly results from the increase of precipitation in this region due to the strengthening and southward shift of westerlies and the decrease of evapotranspiration caused by the cooling during that time.

Key words: arid Northwest China, Little Ice Age (LIA), humidity variability